https://github.com/damianc/math-atan2point

Getting point by distance and angle.
https://github.com/damianc/math-atan2point

Last synced: about 1 month ago
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Getting point by distance and angle.

• Host: GitHub
• URL: https://github.com/damianc/math-atan2point
• Owner: damianc
• Created: 2023-10-16T23:14:31.000Z (about 1 year ago)
• Default Branch: master
• Last Pushed: 2023-10-16T23:49:30.000Z (about 1 year ago)
• Last Synced: 2023-10-17T10:19:26.912Z (about 1 year ago)
• Language: JavaScript
• Size: 1.95 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# math-atan2point

A method for getting a point by distance and angle. While `Math.atan2()` returns an angle between the x-axis and a ray, `Math.atan2Point()` returns the point that creates a ray with given length and angle. 

```

Math.atan2Point(

  angle, distance, origin = [0,0]

)

``` 

## Description

- if $\alpha$ equals $\text{atan2}(P_y,P_x)$

- if $d$ equals $\sqrt{P_x^2 + P_y^2}$ (distance from $(0,0)$ to the point $P$)

- then $\text{atan2Point}(\alpha,d)$ equals $[P_x,P_y]$

```

const p = {x:2, y:4};

const q = {x:5, y:3};

const p0Dist = Math.hypot(p.x, p.y);

const pqDist = Math.hypot(p.x-q.x, p.y-q.y);

const p0Angle = Math.atan2(p.y, p.x);

const pqAngle = Math.atan2(

  q.y-p.y,

  q.x-p.x

);

console.log(

  Math.atan2Point(

    p0Angle, p0Dist

  )

);

// should be: [2,4]

// is: [2,4]

console.log(

  Math.atan2Point(

    pqAngle, pqDist, [p.x,p.y]

  )

);

// should be: [5,3]

// is: [5,3]

```